The present invention relates to a drive unit, and particularly, to a drive unit for a power transmission apparatus that drives a power transmission apparatus in a vehicle provided with an internal combustion engine capable of being automatically stopped and automatically started and the power transmission apparatus having a clutch and being capable of establishing a connection and breaking the connection between an output shaft of the internal combustion engine and a shaft on an axle side by switching an engagement state of the clutch, and a vehicle having the drive unit installed thereon.
As a vehicle of this type in related art, a vehicle has been proposed that is provided with an engine capable of being automatically stopped and automatically started and an automatic transmission for transmitting power from the engine, and that includes, as pumps for generating hydraulic pressure for engaging hydraulically driven clutches or brakes in the automatic transmission, a mechanical oil pump driven by the power from the engine, and an electric oil pump driven by the supply of electric power from a battery (for example, refer to Japanese Patent Application Publication No. JP-A-2003-74689). In this mechanism, when the engine is automatically stopped as the vehicle is stopped, the electric oil pump is driven in place of the mechanical oil pump so that a clutch C1 establishing the first forward speed is held in a state immediately before engagement. Thus, when starting off the vehicle by re-starting the engine and engaging the clutch C1 based on a start-off request from the driver, delay of the engagement of the clutch C1 can be prevented.